Field of the invention
The invention relates to a liquid tank, in particular for motor vehicles, including a tank wall enclosing a tank volume, on the inner side of which tank wall facing the tank volume a relief structure is provided, at least in sections, facing the tank volume.
Particularly in the case of liquid tanks that are designed and intended for installation in motor vehicles, the liquid intended for filling the tank can be readily determined. In principle a liquid tank is suitable for receiving any liquid, as long as the materials used to make the liquid tank are sufficiently stable with respect to a chemical and physical influence of the liquid it is intended to hold. However in motor vehicles in particular, a separate tank is very clearly provided for each operating liquid that is to be stored in the motor vehicle, which separate tank is designed and intended to hold the respective operating fluid. The design is based on the choice of appropriate materials for fabricating the tank, which materials are chemically and physically sufficiently stable with respect to the liquid that is to be contained. The intended purpose is indicated by corresponding markings on the tank and/or by the line connections or routings. The user of the motor vehicle therefore has no choice of which operating fluid he should fill into which tank.
There has been a great deal of discussion in the prior art of how a relative movement of the fluid contained in a tank can be at least impeded relative to the tank containing it. The motive behind this can simply be noise suppression, for example preventing noise emissions due to the liquid sloshing against the tank wall. However the motivation can also be a prevention of undesirable electrostatic charging of the contained liquid due to relative movement of liquid regions relative to one another.
Description of the Related Art
The solutions offered in the prior art for suppressing a liquid movement in a liquid contained in a liquid tank provide, for example, a fiber structure disposed on the inner side of the tank wall, as proposed in DE 38 80 271 T2. Here the fiber structure can be a woven fabric, a fabric, but preferably a tangle of fibers. Here the fiber structure forms a relief structure that deviates from the otherwise smooth inner surface of the tank wall in the sense of the present application.
A liquid tank is known from DE 39 05 611 C2 wherein separate impact elements are provided on the inner surface of the tank wall, in its corner areas, and in its intermeshing areas. Impact elements are applied in the corner areas and intermeshing areas with the aim of minimizing the loss in tank volume to the detriment of the amount of liquid that can be contained. These impact elements can also have a relief structure that deviates from a smooth surface. Thus the exposed surface of an impact element according to DE 39 05 611 C2 facing the tank volume can have an undulating profile or brush-type protruding plastic needles.
DE 100 62 154 A1 also discloses a liquid tank wherein a thread-type structure for noise abatement is provided. In contrast to the liquid tank in the previously mentioned documents, in the liquid tank in DE 100 62 154 A1, the thread-type structure extends throughout the tank volume and is supported by or attached to the tank wall at its longitudinal ends.
A liquid tank is known from U.S. Pat. No. 3,400,854 A, which on the one hand is coated on its inside with a rubber layer, and on the other hand is filled as completely as possible with hollow bodies. In contrast to the previously presented liquid tanks in the prior art, the rubber layer includes no relief structure, but instead is rather smooth on its inner side that is exposed to the tank volume. The rubber layer also serves to seal the tank. The hollow bodies that have been filled into the tank volume serve to reduce a sloshing movement of the liquid in order to reduce possible noise emission from the tank.
A liquid tank for a motor vehicle is also known from U.S. Pat. No. 8,235,241 B2, in the tank volume of which liquid tank hollow bodies are contained. Whereas the tank volume of the previously mentioned liquid tank is filled to the greatest extent possible with loose hollow bodies, the tank volume of the presently discussed liquid tank from the prior art is significantly larger than the volume of the hollow bodies with which it has been filled. However, the hollow bodies filling the tank volume are connected to each other in a net-like manner, wherein the hollow-body network is anchored on the inner side of the tank wall in the corner regions thereof with a certain degree of relative mobility relative to the tank wall.
All of these solutions in the prior art have in common that a physical structure provided to reduce a sloshing movement of the contained liquid is fabricated separately from the tank and is joined to the inner side of the tank in an assembly process. A disadvantage of these solutions is the high expense of fabrication and assembly required to make the known liquid tank.